Apparatus for locking control plungers in slide valve control devices



March 17, 1942. 0 H. JACOB! 2,276,979

APPARATUS FOR LOCKING CONTROL PLUNGERS IN SLIDE VALVE CONTROL DEVICES Filed Sept. 6, 1940 2 Sheets-Sheet 1 Marph 17, 1942.

H. JACOB! APPARATUS FOR LOCKING CONTROL PLUNGERS I-N SLIDE VALVE CONTROL DEVICES Filed Sept. 6, 1940 2 Sheets-Sheet 2 In venzo Z1 Patented Mar. 17,

v UNITED STATES PATENT FFlCE APPARATUS FOR LOCKING CONTROL PLUNGERSIN SLIDE VALVE CONTROL DEVICES Hermann Jacobi, Frankfort-on-the-Main,

Germany, assignor to American Lurgi Corporation, New York New York N. Y., a corporation 0! Application September 6, 1940, Serial No.- 355,703 In Germany December 1, 1938 7 Claims. -(Cl.137-139) a (rotary or plunger slide valve switch), a working cylinder and an hydraulic seal, for actuating oscillating machine parts are known. In addition, it heretofore has been proposed to lock such control members.

An object of the present invention is to provide improved devices for locking control plungers,

which devices will be easy to operate and whose functioning will be dependable. Another inventive object is the provision of a double-acting locking device of the general type above described. A further object of invention is the provision of an improved method of locking control plungers of slide valve control switches. Other inventive objects will be apparent from a consideration of the following description and of the appended claims. I

The invention consists essentially in a new mode of locking control plungers of such switches in which the pressure of the liquid or gaseous pressure fluid effective in the working cylinder is used for locking the control plunger. After actuation of the control plunger, the pressure fluid is first led to a locking piston that in its turn holds the control plunger in the desired position,

whereupon the pressure fluid .is conducted into.

the working cylinder; after the pressure fluid has completed delivery of work force to the working piston in the working cylinder it exerts pressure on the opposite side of the double-acting locking plunger, whereupon equalization of pressure occurs at the two sides of the locking plunger permitting release of the locking member. According to the invention, a difference in pressure is produced in the circulating pressure agent by throttling the pressure-fluid flowing to the working cylinder, this difierence in pressure causing the engagement of a locking plunger in the locked position, whereupon, after cessation of the flow of the pressure fluid to the working cylinder, an equalization in pressure takes place automatically.

The new process for locking control plungers, and improved devices for carrying out that process, will now be explained in greater detail in connection with an illustrative constructional example and with reference to the accompanying drawings, in which:

Fig. 1 is a sectional vii-w of the slide valve switch and the working cylinder with which it cooperates, showing the position of the control sure fluid through the opening [9 in the pipe l3 plunger whenthe pressure agent is kept in circulation without delivering work;

.Fig. 2 is a view similar to that in Fig, 1, and showing a working position of the control plunger; and

Fig. 3 is a similar view showing a modified form of the locking device, in which view another working position of the control plunger is shown.

The specific device-illustrated by the figure of the drawings is adapted for actuating swinging parts, for instance, the landing gear, of airplanes and also for actuatin similar oscillating mechanisms. Y

The pressure fluid, for which oil or a gaseous agent enters chiefly into question, is kept in constant circulation, by meansof a pump l (which may, as is illustrated, be a gear-wheel pump),

through the pipes 1 and 8, the passage opening ll, the recess I8 inside the control plunger 5, the

opening l9 and the pipes l3, M (the latter shownpartly by broken lines) and the collecting receptacle 4. The openings ll and I9 at the same time are connected to the annular passages H and I9, respectively, which latter are cut as grooves into the plunger 5. The pressure chamber 20 with the double-acting locking plunger 24 is connected to the annular passage H. The pressure On the lower plunger surface of plunger 24 is compensated, in the rest position of the control plunger 5, by a counter pressure acting on the top of the locking plunger 24 through the throttle pipe, or excess pressure valve, 22 between the pipes 8 and 23, and the annular passage 23'. In addition, a spring 26 causes the locking plunger 25 carrying locking pin 25 to remain constantly in the disengaged position as long as there is equalization ofpressure on the two sides of the locking plunger.

By displacement of the control plunger 5 to the left, as shown in Fig. 2, the circulation of pres-v is interrupted and, instead, the pressure fluid is carried around through the constricted connecting passage 2|, Or by opening of the excess pressure valve 22, through the passage 23, the opening H, the recess 18 and further the opening 32 with the annular passage 32, through the passage 9 and pipe H into the working cylinder 3. At the same time, the locking plunger 24 is brought to the locked position by the excess pressure making its appearance in the passage 8 and the pressure chamber 20 as shown in Fig. 2. Under the conditions thus obtaining, the pressure fluid pushes the work piston to the right (inthe direction of the arrow) in the working cylinder 3. As soon as the work piston in the working cylinder ,3 has reached theend position of its stroke, in connection with which it has forced the pressure fluid in front of it in the working cylinder through the connecting pipe l2, the passage Ill and the opening l5 into the pipe l5 and thereby into the collection chamber 4, there is an equalization of pressure that was not present before due to the flow of the pressure fluid through the constricted passage 2|. This diflerence in pressure caused by the constricted passage 2| during passage of the pressure fluid produces a greater pressure on the bottom or the plunger 24 than on the top of the, same, so that the locking pin 25, as is shown in Fig. 2, presses into the annular passage 11' and thereby holds the control plunger 5 in the locked position. This locked Dsiti0n is relinquished again at the moment when, upon attaining the end position of the work piston in the working cylinder 3, flow of the pressure fluid ceases and thereby there is regained equalization of pressure between the passages 23 and 2|. Through the annular passage ll in connection with the passage 23, under certain cases the pressure is transmitted to the top of the locking plunger 24 through the connecting passage 21 in the lock pin 25, so that at both sides of the locking plunger equalization in upon displacement of the control plunger to the right, as shown in Fig. 3. The pressure fluid, due to the excess pressure occurring in the pressure chamber 20, presses the locking plunger 24' against the control plunger 5, this locking plunger being constructed here without locking pin and without spring 26, according to a modification of the invention. The locking of the concylinder 3 as desired. Finally the excess pressure valve 22 could likewise be opened by a special handle (not shown) in order to cause equalization of pressure at once and thereby to release the locking plunger 24 (or 24) from its locked position.

The locking of the control plunger according to the invention can be used, in the same way as shown here in the example or the plunger slide valve, on other slide valves likewise, for instance.

rotary valves, with the same success.

I claim:

1. In a slide valve control device :having a double-acting locking plunger, said locking plunger being movable into and out of locking relationship with a slidable control element by a pressure fluid, compression chambers on opposite sides of said plunger, said opposed compression chambers being separately connected with said pressure fluid, throttling means between said pressure fluid and one of said compression chambers eflective upon appropriate movement of said slidable element to produce a diflerence in pressure or pressure fluid in the two compression chambers for moving said locking plunger into locking relationship with said device.

2. In a slide valve control device for actuating a movable-machine part, of the type described,

including a slidable control element, the combination comprising a double-acting locking plunger, said locking plunger being movable into and out of locking relationship with said slidable 4 control element by afluid pressure, a pressure trol plunger 5 is accomplished here solely by the application of the locking plunger 24. For ,increasing its clamping efiect, special frictional surfaces can be provided on the locking plunger, or a special shape can be given the locking plunger surfaces. The clamping effect compensates the pressure of th spring 28, so that the-spring 28 cannot, draw the control plunger 5 back to the middle position. Thereupon, the pressure fluid flows through the excess pressure valve 22, or the constricted passage 21, through the opening 32, the recess [8, the openin I9 in the reverse direction through the passage 10 and the connection pipe l2 into the working cylinder 3 and pushes the work piston in the direction of the arrow, to the left, into its reverse end position. Upon the happening of this event, there is again reached an equalization of pressure between the pipes B and 23 through .the constricted passage 2| and thereby an equalization of pressure at the opposed sides of the plunger 24, i. e., between the annular chamber 32 and the pressure chamber 20. The pressure agent in front of the work piston is led back through the pipes 9, l5 and l 6 into the collection receptacle 4.

The structure of th locking plunger 24' without the locking pin 25 makes it possible to bring back the control plunger 5 each time by hand in overcoming the spring pressure 28, so as-to interrupt the working operation in the working fluid conduit, two opposed. compression chambers on opposite sides of said plunger, each of said opp sed compression chambers being separate from the other and in communication with said pressure fluid conduit, and a throttling means between said pressure fluid conduit and one of said compression chambers'efiective upon appropriate movement of said slidable element to produce a part has reached its end position, an equalization g which the locking plunger is provided on that I of pressure of pressure fluid is automatically eifected in the two compression chambers to permit movement or said locking plunger from lockside thereof adjacent the control plunger with a friction-increasing surface for engaging a surface of the'locking plunger in locking relationship.

5.. The combination defined in claim 2, in which a resilient member presses against one sid of said locking plunger. I

6. The combination deflned in claim 2, in which the throttling means includes a constricted passage between said pressure fluid conduit and one of said compression chambers.

7. The combination deflned in claim 2, in which the throttling means includes a passage between said pressure fluid conduit and one' of said compression chambers and an excess pressure valve in said passage.

' HERMANN JACOBI. 

